In science, astronomers must analyze many observations and separate out those that provide evidence in support of a specific theory. to reinforce the credibility of a theory, astronomers must look for multiple, independent pieces of evidence. consider the following example: astronomers believe that every bright galaxy harbors a supermassive black hole at its center. sort the following observations according to whether they support or do not support this theory.

a. support: fast motions of closely orbiting material in galactic nuclei, powerful jets of high-speed material, exceptionally bright galactic nuclei
b. do not support: stellar black holes in interacting binary systems, globular clusters in the outer galactic haloes, spiral arms in the outer disks of galaxies.